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"During its initial data-collecting dive over Jupiter's poles on Aug. 27, 2016, Juno captured the first-ever photo of the giant planet's faint ring system from the inside, mission team members revealed Thursday (May 25).

The photo, which Juno took with its star-tracking navigation camera, also shows part of the constellation Orion, including the bright star Betelgeuse and the three stars that make up Orion's belt."

"New observations about the extreme conditions of Jupiter’s weather and magnetic fields by University of Leicester astronomers have contributed to the revelations and insights coming from the first close passes of Jupiter by NASA’s Juno mission, announced today (25 May).

The astronomers from the University’s Department of Physics and Astronomy, led by Professor Stan Cowley, the UK science lead for the Juno mission, have led three papers and contributed to four further papers in Geophysical Research Letters, a journal of the American Geophysical Union, that support the first in-depth science results from Juno published in the journal Science."

"Take a trip around Jupiter with NASA’s Juno spacecraft in a time-lapse animation created from a sequence of images taken during the probe’s last close-up flyby of the gas giant May 19.

The orbiter’s JunoCam imager repeatedly scanned across the planet as the craft soared over Jupiter’s north pole, passed within around 2,200 miles (3,500 kilometers) from its turbulent cloud tops, then sailed back into deep space over the south pole."

I'll consider how much gravity data Juno will be able to get. The spacecraft looks like it will stay in a 53-day orbit instead of going to a 14-day one. However, that orbit change would not have changed the spacecraft's perijove (closest point) very much, only its apojove (farthest point). That means that it will still be going to close to its intended closest distance -- and that its orbit will still be nearly parabolic there.

That means that it should still be possible to get good gravity data by tracking the spacecraft.

The gravitational potential generated by an arbitrary distribution of mass is given by this horrible-looking expression:

The C's and S's are gravity coefficients, and some of them have special values. The pure-latitude one Sl0 = 0, and Cl0 = - Jl, where the J is another name. The monopole one, C00 = 1 always. The dipole ones C10, C11, and S11 are set to zero by placing the coordinate origin at the object's center of mass or centroid.

If one imposes rotational symmetry, then all nonzero-m gravity coefficients become zero. Likewise, imposing north-south symmetry makes all odd-l gravity coefficients zero. So one can test for departures from those symmetries by finding the values of the gravity coefficients.

In the rotationally-symmetric case, the first nontrivial one, J2, has value where A and C are the equatorial and polar moments of inertia. Since (moment of inertia) = (distance from reference axis)^2 integrated over (mass), it's evident that J2 tends to be more sensitive to mass closer to the surface unless it fades off with distance rather fast. The higher-l gravity coefficients are likewise even more sensitive to near-surface mass than deep-interior mass. But they should still be valuable as probes of Jupiter's interior, and tests of our ability to model it.

So if Jupiter has a solid core, the gravity coefficient that it will contribute the most to is J2, and even that will be relatively small. But if the core has a mountainous surface, that should show up as departures from rotational and north-south symmetry.

Think the mass of the moons is throwing something off? What you describe there is an ideal situation where Juno is the only moon Jupiter has.

It should be easy to calculate the moons' perturbations of the spacecraft's path. The larger moons' masses are now known to a part in a thousand (1985AJ.....90..364C Page 364), and their orbits are all reasonably well. The most massive of Jupiter's moons, Ganymede, is almost 1/10,000 times as massive as Jupiter.

"NASA's Juno spacecraft has now been orbiting the solar system's largest planet for a year.

Juno arrived at Jupiter on July 4, 2016, after a nearly five-year trek through deep space. Ever since its arrival, the probe has been peering at the gas giant intently, gathering data that should help scientists better understand Jupiter's formation and evolution."

"Images of Jupiter's Great Red Spot reveal a tangle of dark, veinous clouds weaving their way through a massive crimson oval. The JunoCam imager aboard NASA's Juno mission snapped pics of the most iconic feature of the solar system's largest planetary inhabitant during its Monday (July 10) flyby. The images of the Great Red Spot were downlinked from the spacecraft's memory on Tuesday and placed on the mission's JunoCam website Wednesday morning."

A dynamic storm at the southern edge of Jupiter's northern polar region dominates this Jovian cloudscape, courtesy of NASA's Juno spacecraft. This storm is a long-lived anticyclonic oval named North North Temperate Little Red Spot 1 (NN-LRS-1); it has been tracked at least since 1993, and may be older still. An anticyclone is a weather phenomenon where winds around the storm flow in the direction opposite to that of the flow around a region of low pressure.

It is the third largest anticyclonic oval on the planet, typically around 3,700 miles (6,000 kilometers) long. The color varies between red and off-white (as it is now), but this JunoCam image shows that it still has a pale reddish core within the radius of maximum wind speeds.

NASA's Juno mission at Jupiter began its seventh close science flyby of the Jovian giant Friday (Sept. 1).

The Juno probe is in an orbit around Jupiter that brings it between the planet's cloud tops and a belt of harsh radiation that encircles the planet. Flying through the radiation belt would destroy the probe's electronics. To maintain this orbit, the probe must swing far out beyond the planet, and dip inside the radiation belt every 53 days. (This is the probe's 8th total flyby of Jupiter; the first one was done without the science instruments turned on.)

NASA’s spinning Juno spacecraft had its seventh science flyby over Jupiter’s cloud tops on Friday, September 1st at 21:49 UTC, coming as close as 3,500 Kilometers to the planet’s colorful cloud tops.

Residing in a highly elliptical orbit around the Gas Giant, Juno only comes close to Jupiter’s enigmatic cloud tops every 53 days after a decision made by the mission team to forego a planned orbit reduction maneuver last October due to concerns associated with the craft’s propulsion system.

Speeding past Jupiter from north to south, Juno had its camera, spectrometers, particle sensors and cloud-penetrating instruments up and running to probe Jupiter’s dense atmosphere as it zipped past.

The spacecraft’s JunoCam instrument – not directly considered part of the science payload – delivered a number of images from this latest pass. JunoCam images in their raw form are posted on the project website for citizen scientists to apply their talents stitching, zooming, contrasting and color-calibrating to bring out the best detail in the tantalizing images – a concept that has worked extremely well for this mission and is likely to find its way into several missions in NASA’s not too distant future.

"After the Sun, Jupiter has by far the strongest and biggest magnetic field in our solar system — it stretches about 12 million miles from east to west, almost 15 times the width of the Sun. (Earth’s, on the other hand, could easily fit inside the Sun — except for its outstretched tail.) Jupiter does not have a molten metal core; instead, its magnetic field is created by a core of compressed liquid metallic hydrogen."

Data returned Tuesday, Oct. 31, indicate that NASA's Juno spacecraft successfully completed its eighth science flyby over Jupiter's mysterious cloud tops on Tuesday, Oct. 24. The confirmation was delayed by several days due to solar conjunction at Jupiter, which affected communications during the days prior to and after the flyby.

Solar conjunction is the period when the path of communication between Earth and Jupiter comes into close proximity with the Sun. During solar conjunction, no attempts are made to send new instructions or receive information from Juno, as it is impossible to predict what information might be corrupted due to interference from charged particles from the Sun.

Instead, a transmission moratorium is put into place; engineers send instructions prior to the start of solar conjunction and store data on board for transmission back to Earth following the event.

"All the science collected during the flyby was carried in Juno's memory until yesterday, when Jupiter came out of solar conjunction," said the new Juno project manager, Ed Hirst, from NASA's Jet Propulsion Laboratory in Pasadena, California.

Jupiter's southern hemisphere is a swirling, curling sea of colorful clouds in a new image from NASA's Juno spacecraft and two citizen scientists.

The new image comes from data collected by the JunoCam instrument on Oct. 24, 2017, as Juno performed its ninth close flyby of Jupiter (its eighth science flyby), according to a statement from NASA. The raw data from the instrument were uploaded to the JunoCam website, and citizen scientists Gerald Eichstädt and Seán Doran took that data and processed it to create the image above. [Amazing Jupiter Photos by Juno and Citizen Scientists]

The image captures the intricate currents that Juno has revealed in Jupiter's cloud tops. The spacecraft was 20,577 miles (33,115 kilometers) above the tops of the clouds when this image was taken, at a latitude of minus 52.96 degrees, according to the statement.

The Juno spacecraft captured this image when the spacecraft was only 11,747 miles (18,906 kilometers) from the tops of Jupiter's clouds - that's roughly as far as the distance between New York City and Perth, Australia.

The color-enhanced image, which captures a cloud system in Jupiter's northern hemisphere, was taken on Oct. 24, 2017 at 10:24 a.m. PDT (1:24 p.m. EDT) when Juno was at a latitude of 57.57 degrees (nearly three-fifths of the way from Jupiter's equator to its north pole) and performing its ninth close flyby of the gas giant planet.

I'm here for two days to cover Juno, Cassini, Curiosity, and one Earth-as-a-planet session. I'm taking notes for longer posts that I'll get to later this week, but thought I would share a brief news item from yesterday: Juno has obtained some surprisingly good images of bright spots showing volcanism on Jupiter's moon Io, which are nicely complementary to work being done from Earth. I wanted to post about this because all the Io scientists I've found at AGU were completely unaware of these observations and didn't see the talk. So Io fans, a call to action: go find the JIRAM team today!

JunoCam has been wowing us with gorgeous images of Jupiter since Juno arrived. That's its entire reason for existence: the fact that it would've been criminal not to send a camera on a Jupiter mission, even though the camera wasn't required to achieve Juno's interior-focused science objectives. Time and again, though, small cameras have yielded unexpected scientific discoveries. At last week's American Geophysical Union (AGU) meeting, JunoCam team leader Candy Hansen gave the first public presentation focused on the science achieved by JunoCam, and asked the gathered scientific community to join in.

It’s been just three days since NASA’s Juno orbiter had its most recent close encounter with Jupiter, but image-processing gurus are already sharing sweet views of the giant planet’s cloud patterns.

The probe was launched in 2011 and arrived at Jupiter on the Fourth of July last year. Since then, its elliptical orbit has been taking it close to the planet’s cloud tops every 54 days — an event known as perijove. Dec. 16’s photo op is known as Perijove 10.

The probe’s primary scientific mission is to study Jupiter’s magnetic field, composition and gravity field, but it also has a camera known as JunoCam that takes closeups for public consumption. JunoCam’s raw images are served up for anyone to process, and some have gotten amazingly good at it.

Anyone can upload processed images to the Juno mission’s online gallery, which features many of the best snapshots. For Perijove 10, views of Jupiter’s mid-northern latitudes are the house specialty.

You’ll find some choice cuts on Twitter and Unmanned Spaceflight as well. While we wait for Perijove 11 in February, feast your eyes on these highlights:

The Juno mission is all about understanding Jupiter’s interior. Last week at the American Geophysical Union Meeting in New Orleans, the mission announced that the Great Red Spot has roots 300 kilometers deep, based on data from the microwave radiometer. But Juno's microwave instrument can only peer a few hundred kilometers into a planet that’s 70,000 kilometers deep. To get deeper than that, Juno uses gravity and magnetic-field measurements.

At AGU, gravity scientists reported that Jupiter’s windy belts and zones penetrate much deeper than the Red Spot, to 3,000 kilometers. One way of interpreting this: Jupiter has an atmosphere that is 3,000 kilometers thick. Below that, Jupiter’s interior behaves more as a solid body -- it behaves like Earth does when it rotates. Its layers may be liquid in some places and solid in others, but even the liquid layers are all rotating together as a single entity. Several people shared aspects of this result, but Yohai Kaspi led the effort.

Trying to put the 3,000-kilometer depth in perspective, Kaspi said (my notes from his talk, so not verbatim): “If you're an atmospheric scientist...it contains 1% of the mass of Jupiter. It's huge. But from an internal model standpoint, it's just an atmosphere, it doesn't go down to depth, it’s not the concentric [differentially rotating] cylinders we were thinking about before.” In other words -- atmospheric scientists care a lot about it, but it's small enough for physicists to neglect. Everybody wins!

That, dear readers, is a major Juno result, a brand-new insight into the dynamics of the interior of Jupiter. It's tempting to end the post there, but I want to explain a little bit about how scientists figured it out from gravity data. It won't be easy because it involves a mathematical concept called spherical harmonics. “Spherical harmonics” sound esoteric but they're part of the basic vocabulary of the scientists who discuss gravitational and magnetic fields generated by solar system worlds, which means it’s going to come up on Juno again and again. So I'm going to give a shot to explaining the concept.

The ribbons of multicolored gas that make up Jupiter's atmosphere are on display in two new images from NASA's Juno probe.

In one of the new images, the ribbons of gas that wrap around Jupiter's equator are shown in stunning resolution, revealing detailed structures in the clouds. With this level of detail, the bands of gas start to resemble solid materials: An orange-tinted region looks like a knotty wood plank, and a speckled, whitish-blue layer looks like a sandy river bottom.

In the second image, the planet's south pole is rendered in bright colors that highlight how the bands of gas remain separate from each other, despite their stormy nature.

While most NASA workers were sipping coffee on Wednesday morning, the space agency's Juno probe was screaming over the cloud tops of Jupiter at roughly 130,000 miles per hour.
The $1 billion mission sends Juno swinging around the planet on an elliptical orbit about once every 53.5 days. The spacecraft made its eleventh close pass, or perijove, around 9:36 a.m. ET on February 7, taking some gorgeous photos of the gas giant in the process.

The new images reveal giant bands of swirling storms and a unusually bright, pillowy cloud, among other features.

Sometimes it takes Juno days (or even weeks) to beam back all of its raw image data, but the JunoCam instrument's unparalleled view is always worth the wait. The images shared online rarely come from NASA, though: The data gets posted to a special website where a community of science and art enthusiasts can take the black-and-white files and tweak them into stunning color pictures, which they upload back to the site.

Here are some of the prettiest new images we've seen from Juno's latest orbit.

Overall, NASA’s Juno spacecraft in orbit of Jupiter is in good health and good condition as the probe heads toward its two-Earth year anniversary in orbit of the giant planet this July. The spacecraft’s good health bodes well in terms of NASA’s upcoming decision of whether to end the mission this summer or extend it, a decision that is largely understood to be related to how the spacecraft holds up to Jupiter’s intense radiation field.